This invention relates generally to the art of power transmission, and more specifically concerns a system for transmitting microwave power from solar power generators in space to earth and subsequent conversion of the received power to a useful form.
There is a recognized need for new sources of power, and considerable interest and effort has recently been directed toward the utilization of solar energy. Electrical power may be generated directly from the sun by solar cells, or indirectly by solar collectors. One suggestion has been to locate such devices, particular solar cells, in space satellites, where they are not subject to the degrading effects of the earth's atmosphere.
The electrical power produced by the satellite-based solar power generators is then transmitted in a continuous wave at microwave frequencies to receiving stations on the earth. There remains the problem, however, of efficiently converting the microwave energy received from the satellite into a useful form, such as a 60 Hertz three phase signal. The primary conversion method known in the prior art involves first rectifying the received continuous wave microwave power to produce a DC current and then converting the DC current to a 60 Hertz three phase signal by means of inverters. This system, however, is sufficiently complex and expensive that it is impractical when compared to competing energy systems.
Efficiency is another significant problem with such systems. Polarization alignment must be constantly maintained between the transmitting and receiving antennas, since the receiving antenna on earth is fixed while the transmitting antenna on the satellite is continuously moving. Without continuous alignment of the antennas, power is lost and the efficiency of the system reduced correspondingly. The equipment necessary to maintain polarization alignment adds considerably to the already high cost of the system. Thus, satellite power beaming stations have been heretofore considered to be impractical.
Accordingly, it is a general object of the present invention to provide a system for transmitting electrical energy from space and subsequently converting that energy into a practical power signal which overcomes one or more of the disadvantages of the prior art listed above.
It is another object of the present invention to provide such a system which produces a three phase 60 Hertz signal, without the use of expensive inverters and the like.
It is a further object of the present invention to provide such a system which does not require continuous alignment of the receiving and transmitting antennas.
It is an additional object of the present invention to provide such a system which utilizes microwave power in the form generated by existing solar power generators.